The objective of this application is to obtain support to fund travel expenses and conference fees (including registration, room and board) for the invited speakers and discussion leaders as well as the Chair and Vice- chair, at the Gordon Research Conference on Fertilization and the Activation of Development, to be held at Holderness School, Plymouth, New Hampshire, August 15-20, 1993. This conference has been held every two years since 1974. It is the only Gordon Conference concerned with the interaction of the male and the female gametes in the vital process of fertilization and activation of the fertilized egg to begin the process of embryo formation. It provides a venue for the interaction of biochemists, cell biologists, molecular biologists, physiologists, and biophysicists working in the field. This conference has been singularly successful in fostering collaborations between workers in the middle and on the periphery of the field, between researchers of similar and widely disparate experience and seniority, and between research laboratories in this country and Japan, Europe, Australia, and Latin America. These collaborations have borne many fruitful results. There will be nine sessions in the conference, following the Gordon Conference format. 1) Sperm interactions with the follicular environment and the zona pellucida, 2) sperm chemotaxis, 3) sperm interactions with the egg plasma membrane, 4) egg activation mechanisms, 5) insights into fertilization biology from studies of other cells: cell adhesion and signalling, 6) fertilization in plant systems, 7) current topics and contributed papers, 8) plenary lecture, 9) early events in pattern formation. Session 8 is the plenary lecture, a particular tradition of this Conference. This year's lecturer will be Dr. Tim Hunt, from the Imperial Cancer Research Fund, Herts, England; the title of his lecture will be, "Control of the two meiotic and first mitotic cell cycles in clams and frogs."